The developers over at XDA has created an Android L theme for exDialer app. This theme will bring the same look of Android L dialer on your phone – the interface, color scheme, and even the touch sound feels the same. Installation & Settings:
- Download exDialer app (it is a trial version) and install it (download link at source). 
- Download Android L dialer theme and install it (download link at source). 
- Open exDialer app and tap menu button (3 small dots). Select ‘Preferences’ and tap ‘Theme’. 
- Select ‘Android L’ from the list and apply it. Enjoy the new Android L dialer user interface with round icons, light blue color scheme and touch sound. From the ‘Preferences’ menu you can change appearance (text size, display size, etc.), language, behavior (audible touch-tone, haptic feedback, etc.) and more of the dialer (source & download)